The Experts below are selected from a list of 315 Experts worldwide ranked by ideXlab platform
B. Biagioli - One of the best experts on this subject based on the ideXlab platform.
-
NT-proBNP and cardiac Cycle Efficiency changes during extubation process in critically ill patients
Critical Care, 2013Co-Authors: Federico Franchi, P Mongelli, M Cozzolino, B. Galgani, C Ragozzino, C Bianchi, B. BiagioliAbstract:Several factors can lead to weaning failure from mechanical ventilation (MV). Among these, cardiac dysfunction is one of the main causes. NT-proBNP has been proposed as a biomarker of cardiovascular function during weaning from MV. Unfortunately it does not provide for a continuous monitoring of cardiac function. Pulse wave analysis may serve as a continuous bedside monitoring tool of cardiovascular performance. Cardiac Cycle Efficiency (CCE) is an indirect index of left ventricular performance obtained by the pulse contour method MostCare (Vygon, Padova, Italy). The aim of this study was to evaluate the correlation between NT-proBNP and CCE and the potential usefulness of such variables during the weaning process from MV.
-
Cardiac Cycle Efficiency correlates with pro-B-type natriuretic peptide in cardiac surgery patients
Critical Care, 2008Co-Authors: Sabino Scolletta, Federico Franchi, Filippo Carlucci, Antonella Tabucchi, Sm Romano, P. Giomarelli, B. BiagioliAbstract:Cardiac Cycle Efficiency (CCE) can be calculated by the pressure recording analytical method (PRAM), a less invasive pulse-contour system that can provide beat-to-beat monitoring of cardiac output (CO). CCE is an innovative parameter that ranges from -1 to +1, with -1 being the worse and +1 the best possible Efficiency of the cardiac Cycle (that is, better ventricular–arterial coupling). Pro-BNP-type natriuretic peptide (pro-BNP) is predominantly secreted from the cardiac ventricles in response to increases in ventricular wall stress (VWS). Pro-BNP has been shown to correlate with myocardial hypertrophy and dysfunction [1]. We studied the feasibility of the CCE by PRAM when compared with pro-BNP to monitor the VWS and myocardial impairment and recovery in cardiac surgery.
Sabino Scolletta - One of the best experts on this subject based on the ideXlab platform.
-
relationship between n terminal pro b type natriuretic peptide nt probnp and cardiac Cycle Efficiency in cardiac surgery
Biomedicine & Pharmacotherapy, 2010Co-Authors: Sabino Scolletta, Federico Franchi, Filippo Carlucci, Sm Romano, Giulia Ranaldi, Bonizella BiagioliAbstract:N-terminal pro-B-type natriuretic peptide (Nt-proBNP) is a peptide released from myocardium in response to ventricular wall stress and dysfunction. Nt-proBNP plasma levels are elevated in a variety of cardiovascular disorders and are largely used for diagnosis and treatment of cardiac diseases. The cardiac Cycle Efficiency (CCE) is a haemodynamic variable that represents the left ventricle wall stress and the heart's effort to maintain an adequate blood flow to tissues. We investigated the relationship between Nt-proBNP and CCE values in patients undergoing cardiac surgery. Twenty-five patients undergoing aortic valve replacement were studied. Plasma Nt-proBNP concentrations were performed by electroluminescence immunoassay before starting surgery (t0), at the end of extracorporeal circulation (t1) and 3 hours after surgery (t2). CCE measurements were acquired at the same intervals and correlations with Nt-proBNP levels were calculated. Nt-proBNP plasma concentration was 1430 ± 341 pg/ml at t0, peaked significantly at t1 (2129 ± 561 pg/ml, p<0.001) and moderately decreased at t2 (1924 ± 477 pg/ml, p<0.05). A direct correlation between Nt-proBNP measured at t0 and t1 was found (r=0.91, p<0.001). Overall, a negative correlation between CCE and proBNP values was found (r=-0.89, p<0.01). Correlations between CCE and Nt-proBNP were -0.91, -0.83 and -0.88, at t0, t1 and t2, respectively (p<0.01). Nt-proBNP levels reflect the severity of left ventricle dysfunction in patients undergoing cardiac surgery. CCE correlated well with serum Nt-proBNP levels and seems to be a useful variable to monitor the left ventricular stress and recovery during the various phases of surgery.
-
Cardiac Cycle Efficiency correlates with pro-B-type natriuretic peptide in cardiac surgery patients
Critical Care, 2008Co-Authors: Sabino Scolletta, Federico Franchi, Filippo Carlucci, Antonella Tabucchi, Sm Romano, P. Giomarelli, B. BiagioliAbstract:Cardiac Cycle Efficiency (CCE) can be calculated by the pressure recording analytical method (PRAM), a less invasive pulse-contour system that can provide beat-to-beat monitoring of cardiac output (CO). CCE is an innovative parameter that ranges from -1 to +1, with -1 being the worse and +1 the best possible Efficiency of the cardiac Cycle (that is, better ventricular–arterial coupling). Pro-BNP-type natriuretic peptide (pro-BNP) is predominantly secreted from the cardiac ventricles in response to increases in ventricular wall stress (VWS). Pro-BNP has been shown to correlate with myocardial hypertrophy and dysfunction [1]. We studied the feasibility of the CCE by PRAM when compared with pro-BNP to monitor the VWS and myocardial impairment and recovery in cardiac surgery.
Federico Franchi - One of the best experts on this subject based on the ideXlab platform.
-
NT-proBNP and cardiac Cycle Efficiency changes during extubation process in critically ill patients
Critical Care, 2013Co-Authors: Federico Franchi, P Mongelli, M Cozzolino, B. Galgani, C Ragozzino, C Bianchi, B. BiagioliAbstract:Several factors can lead to weaning failure from mechanical ventilation (MV). Among these, cardiac dysfunction is one of the main causes. NT-proBNP has been proposed as a biomarker of cardiovascular function during weaning from MV. Unfortunately it does not provide for a continuous monitoring of cardiac function. Pulse wave analysis may serve as a continuous bedside monitoring tool of cardiovascular performance. Cardiac Cycle Efficiency (CCE) is an indirect index of left ventricular performance obtained by the pulse contour method MostCare (Vygon, Padova, Italy). The aim of this study was to evaluate the correlation between NT-proBNP and CCE and the potential usefulness of such variables during the weaning process from MV.
-
relationship between n terminal pro b type natriuretic peptide nt probnp and cardiac Cycle Efficiency in cardiac surgery
Biomedicine & Pharmacotherapy, 2010Co-Authors: Sabino Scolletta, Federico Franchi, Filippo Carlucci, Sm Romano, Giulia Ranaldi, Bonizella BiagioliAbstract:N-terminal pro-B-type natriuretic peptide (Nt-proBNP) is a peptide released from myocardium in response to ventricular wall stress and dysfunction. Nt-proBNP plasma levels are elevated in a variety of cardiovascular disorders and are largely used for diagnosis and treatment of cardiac diseases. The cardiac Cycle Efficiency (CCE) is a haemodynamic variable that represents the left ventricle wall stress and the heart's effort to maintain an adequate blood flow to tissues. We investigated the relationship between Nt-proBNP and CCE values in patients undergoing cardiac surgery. Twenty-five patients undergoing aortic valve replacement were studied. Plasma Nt-proBNP concentrations were performed by electroluminescence immunoassay before starting surgery (t0), at the end of extracorporeal circulation (t1) and 3 hours after surgery (t2). CCE measurements were acquired at the same intervals and correlations with Nt-proBNP levels were calculated. Nt-proBNP plasma concentration was 1430 ± 341 pg/ml at t0, peaked significantly at t1 (2129 ± 561 pg/ml, p<0.001) and moderately decreased at t2 (1924 ± 477 pg/ml, p<0.05). A direct correlation between Nt-proBNP measured at t0 and t1 was found (r=0.91, p<0.001). Overall, a negative correlation between CCE and proBNP values was found (r=-0.89, p<0.01). Correlations between CCE and Nt-proBNP were -0.91, -0.83 and -0.88, at t0, t1 and t2, respectively (p<0.01). Nt-proBNP levels reflect the severity of left ventricle dysfunction in patients undergoing cardiac surgery. CCE correlated well with serum Nt-proBNP levels and seems to be a useful variable to monitor the left ventricular stress and recovery during the various phases of surgery.
-
Cardiac Cycle Efficiency correlates with pro-B-type natriuretic peptide in cardiac surgery patients
Critical Care, 2008Co-Authors: Sabino Scolletta, Federico Franchi, Filippo Carlucci, Antonella Tabucchi, Sm Romano, P. Giomarelli, B. BiagioliAbstract:Cardiac Cycle Efficiency (CCE) can be calculated by the pressure recording analytical method (PRAM), a less invasive pulse-contour system that can provide beat-to-beat monitoring of cardiac output (CO). CCE is an innovative parameter that ranges from -1 to +1, with -1 being the worse and +1 the best possible Efficiency of the cardiac Cycle (that is, better ventricular–arterial coupling). Pro-BNP-type natriuretic peptide (pro-BNP) is predominantly secreted from the cardiac ventricles in response to increases in ventricular wall stress (VWS). Pro-BNP has been shown to correlate with myocardial hypertrophy and dysfunction [1]. We studied the feasibility of the CCE by PRAM when compared with pro-BNP to monitor the VWS and myocardial impairment and recovery in cardiac surgery.
M. De Paepe - One of the best experts on this subject based on the ideXlab platform.
-
RAISING Cycle Efficiency BY INTERCOOLING IN AIR-COOLED GAS TURBINES
Applied Thermal Engineering, 2006Co-Authors: Hugo Canière, Arnout Willockx, Erik Dick, M. De PaepeAbstract:Abstract The working temperature of a gas turbine, necessary to achieve high Efficiency, makes cooling of the first turbine stages unavoidable. Air and steam can be used for cooling. A model for an air-cooled gas turbine based on the work of Young and Wilcock [J.B. Young, R.C. Wilcock, ASME J. Turbomachinery 124 (2002) 207–221] is implemented in Aspen™. Simple Cycle calculations with realistic parameters of current machines are made and confirm the results of Wilcock et al. [R.C. Wilcock, J.B. Young, J.H. Horlock, ASME J. Eng. Gas Turb. Power 127 (2005) 109–120] that increasing the turbine inlet temperature no longer means an increase in gas turbine Cycle Efficiency. This conclusion has important consequences for gas turbines because it breaks with the general accepted trend of increasing the TIT. An intercooled gas turbine Cycle is intensively investigated, taking the turbine cooling into account. Intercooling not only lowers the work of compression, but also lowers cooling air temperatures. The major influences of the intercooling on the gas turbine Cycle are mapped and explained. Optimum intercooling pressure for maximum gas turbine Cycle Efficiency is much lower than halfway compression. A simulation of the LMS100, the most recent gas turbine on the market from GE Energy, is made to verify the simulation methodology. The claimed intercooled Cycle Efficiency of 46% is confirmed. Further increasing the pressure ratio and TIT can still improve the performance of the intercooled gas turbine Cycle.
Martine Baelmans - One of the best experts on this subject based on the ideXlab platform.
-
optimal pressure drop ratio for micro recuperators in small sized gas turbines
Applied Thermal Engineering, 2008Co-Authors: T Stevens, Martine BaelmansAbstract:Heat recuperation is often used to improve the overall Cycle Efficiency of standard gas turbines. Hereby a high heat exchanger effectiveness and low pressure drops are favourable to achieve maximal Cycle Efficiency. Finding a compromise between these conflicting requirements is the main challenge in recuperator design. In this paper it is shown that the optimal cold and hot side pressure drops of a micro recuperator are uniquely correlated when integrated in a gas turbine. For an optimized microchannel recuperator, the ratio of the cold side pressure drop over the hot side one is only a function of gas turbine properties and primarily depends on the compressor pressure ratio. Based on these findings, a simplified optimization procedure is applied to design a micro recuperator in a 1.5 kW gas turbine. It is shown that the results of this optimization are almost identical to the full multi-dimensional optimization with an accuracy of approximately 1% on geometrical parameters and an excellent agreement for Cycle Efficiency.
-
requirements for recuperators in micro gas turbines
Proceedings of the 4th International Workshop on Micro and Nano Technology for Power Generation and Energy Conversion Applications, 2004Co-Authors: T Stevens, Filip Verplaetsen, Martine BaelmansAbstract:Heat recuperation is a well known mean to improve the overall Cycle Efficiency of a standard gas turbine. Scaling a gas turbine to smaller dimensions has in general a negative influence on pressure ratio, turbine inlet temperature and pressure drops, and thus decreases the overall Cycle Efficiency. A thermodynamic analysis is performed to evaluate heat recuperation in micro gas turbines with respect to pressure drops and heat exchanger effectiveness as a function of gas turbine scaling. For a specific heat exchanger configuration the optimal recuperator volume and optimal channel dimensions are determined. Design requirements for the recuperator are established. This results in an assessment of suitable recuperator configurations for micro gas turbines.
